3 MeV Proton Radiation Tolerance Study of Ultra-thin Gallium Arsenide Solar Cells for Space Applications

Ultra-thin single-junction GaAs solar cells with an 80 nm absorber layer were fabricated and exposed to 3 MeV proton radiation at a range of fluences. Off-wafer devices with an integrated Ag back surface mirror were irradiated as well as on-wafer devices with no mirror. Both 80 nm device designs exhibited high tolerance to extremely high proton fluences with no decrease in short circuit current. They also showed higher absolute maximum power values once moderate to high fluences were achieved when compared to devices with absorber layers of 800 and 3500 nm.